共有10项的数列{an}的通项an=2007-10n2008-10n，则该数列中
题型：选择题
问题：
共有10项的数列{an}的通项an=
|
题型：选择题
In a surprising discovery about where higher life can survive, scientists have found a shrimp -like creature and a jellyfish swimming beneath an Antarctic ice sheet.
About 180 meters below the ice where no light can get through, scientists had figured nothing much more than a few microbes (微生物) could exist.
That’s why a NASA team was surprised when they lowered a video camera to get the first long look at the underbelly of an ice sheet in Antarctica. A curious shrimp-like creature came swimming by and then parked itself on the camera’s cable. Scientists also pulled up a tentacle (触须) they believe came from a jellyfish.
“We were operating on the presumption that nothing’s there.” said NASA ice scientist Robert Bindschadler. “It was a shrimp you’d enjoy havin
g on your plate.”
“We were just gaga (狂热的) over it,” he said when talking about the 7.5cm long, orange creature starring in their two-minute video. Technically, it’s not a shrimp. It’s a Lyssianasid amphipod, which is distantly related to the shrimp.
The video is likely to inspire experts to rethink what they know about life in harsh environments. And it has scientists thinking that if shrimp-like creatures can live below 180 meters of Antarctic ice in freezing dark water, what about other cold places? What about Europa, a frozen moon of Jupiter?
Cynan Ellis – Evans, a scientist of the British Antarctic Survey called the finding fascinating. He said it was possible the creatures swam in from far away and don’t live there permanently.
But Kim, who is a co-author of the study, doubts it. “The site in West Antarctica is at least 19 km from open seas. Bindschadler drilled a 20 cm-wide hole and was looking at a tiny amount of water. That means it’s unlikely that two creatures swam from great distances and were captured randomly in that small area,” she said.
“Yet scientists were puzzled at what the food source would be for these creatures. While some microbes can make their own food out of chemicals in the ocean, complex life like the shrimp can’t,” Kim said.
“So how do they survive? That’s the key question.” Kim said.
“It’s pretty amazing when you find a huge puzzle like that on a planet where we thought we know everything.” Kim said.
小题1:. Scientists had believed that harsh environments could only have been populated by ______ .
A．jellyfish
B．mammals
C．microbes
D．shrimp-like creatures小题2:According to Kim, the shrimp-like creature _________ .
A．swam great distances to Antarctic
B．has always lived in the area
C．gradually evolved from shrimps
D．has nothing in common with shrimps小题3:The finding is significant in that __________.
A．it marks NASA’S first Antarctic biological study
B．it proves there is marine life in the Antarctic
C．it could inspire further study of life in harsh environments
D．it shows that Lyssianasid amphipod is closely related to shrimps小题4:. The last three paragraphs suggest that __________.
A．researchers will look at the places the creatures came from
B．ice scientists will drill deeper to find more creatures
C．scientists know very little about the planet they live o
n
D．further research will be done about what the creatures live on